伴随长期演进(Long Term Evolution,LTE)标准的应用,对上下行链路传输速率的需求大幅提高,使得分布式基站传输的数据量也对应增长,而目前硬件设备所能提供的接口速率是有限的。要解决这种不匹配的情况,可以在传输前对基站数据进行压缩...伴随长期演进(Long Term Evolution,LTE)标准的应用,对上下行链路传输速率的需求大幅提高,使得分布式基站传输的数据量也对应增长,而目前硬件设备所能提供的接口速率是有限的。要解决这种不匹配的情况,可以在传输前对基站数据进行压缩。鉴于基站数据的统计分布和合成孔径雷达数据的统计分布相似,本文参考合成孔径雷达(Synthetic Aperture Radar,SAR)数据的压缩方法—分块自适应量化(Block adaptive quantization)压缩算法,将该算法改进后应用于基站数据压缩。该方法首先将IQ数据(In-phase and quadrature data,IQ data)分块,通过变换使得数据块服从标准正态分布,将块内数据与最佳电平阈值进行比较然后编码。计算机仿真结果表明,BAQ算法能够应用于压缩IQ数据。展开更多
When the saturation degree （SD） of space-borne SAR raw data is high, the performance of conventional block adaptive quantization （BAQ） deteriorates obviously. In order to overcome the drawback, this paper studies ...When the saturation degree （SD） of space-borne SAR raw data is high, the performance of conventional block adaptive quantization （BAQ） deteriorates obviously. In order to overcome the drawback, this paper studies the mapping between the average signal magnitude （ASM） and the standard deviation of the input signal （SDIS） to the A/D from the original reference. Then, it points out the mistake of the mapping and introduces the concept of the standard deviation of the output signal （SDOS） from the A/D. After that, this paper educes the mapping between the ASM and SDOS from the A/D. Monte-Carlo experiment shows that none of the above two mappings is the optimal in the whole set of SD. Thus, this paper proposes the concept of piecewise linear mapping and the searching algorithm in the whole set of SD. According to the linear part, this paper gives the certification and analytical value of k and for nonlinear part, and utilizes the searching algorithm mentioned above to search the corresponding value of k. Experimental results based on simulated data and real data show that the performance of new algorithm is better than conventional BAQ when raw data is in heavy SD.展开更多
文摘When the saturation degree （SD） of space-borne SAR raw data is high, the performance of conventional block adaptive quantization （BAQ） deteriorates obviously. In order to overcome the drawback, this paper studies the mapping between the average signal magnitude （ASM） and the standard deviation of the input signal （SDIS） to the A/D from the original reference. Then, it points out the mistake of the mapping and introduces the concept of the standard deviation of the output signal （SDOS） from the A/D. After that, this paper educes the mapping between the ASM and SDOS from the A/D. Monte-Carlo experiment shows that none of the above two mappings is the optimal in the whole set of SD. Thus, this paper proposes the concept of piecewise linear mapping and the searching algorithm in the whole set of SD. According to the linear part, this paper gives the certification and analytical value of k and for nonlinear part, and utilizes the searching algorithm mentioned above to search the corresponding value of k. Experimental results based on simulated data and real data show that the performance of new algorithm is better than conventional BAQ when raw data is in heavy SD.
